Such a conveying device is known from DE 198 24 846. The known conveying device is arranged between a blow-molding machine used for producing plastic bottles and a filling machine for filling these bottles. The conveying device comprises a buffer for temporarily storing bottles as well as a large number of star wheels. In particular, a transfer star wheel is provided, which is used for charging and discharging the buffer as well as for directly conveying the bottles between the two machines without making use of the buffer. The transfer star wheel communicates through respective transfer sites with the outfeed conveyor of the blow-molding machine and with the infeed conveyor of the filling machine. The transfer star wheel additionally communicates via a third transfer site with the buffer (through a charging and discharging star wheel). This charging and discharging star wheel is switched inoperative when direct conveying between the machines is possible. However, this structural design operates with a comparatively low flexibility and it only works when the conveying speeds are identical on both sides of the transfer star wheel.
According to a further embodiment, the charging and discharging star wheel is replaced by a conveyor unit which can be pivoted after the fashion of a track switch. When occupying a first position, the conveyor unit connects the transfer star wheel to the buffer and, when occupying a second position, the conveyor unit connects the transfer star wheel to the infeed point of a downstream machine so as to effect direct conveying. Also this embodiment needs identical speeds. In addition, the emptying of the buffer necessitates an inversion of the conveying direction, which is comparatively difficult to control.
A conveying device making use of a deflection into a buffer after the fashion of a track switch is known e.g. also from U.S. Pat. No. 6,152,291. The conveying device comprises a linear conveyor in the form of a conveyor belt communicating via a respective kind of track switch with an infeed conveyor and with an outfeed conveyor of a dynamic buffer. Whereas the infeed and outfeed conveyors of the buffer can operate at different speeds, the speed at which the linear conveyor can supply the articles to the first track switch and transport the articles away from the second track switch is determined by the direct connection through the continuous conveyor belt.